This invention relates to a process for alkylation at carbon and phosphorus sites in an aqueous medium using precious metal catalysts containing sulfonated triarylphosphines (STP) of the generic formula P(C.sub.6 H.sub.4 SO.sub.3.sup.-).sub.X (C.sub.6 H.sub.5).sub.Y (X+Y=3).
A review of the use of sulphonated phosphines in homogeneous catalysis is "Homogeneous Catalysis in Water" by Emile G. Kuntz, Chemtech, Sept. 1987, p. 570. Review of the Heck reaction and Pd catalyzed alkylations in non-aqueous media can be found in J. Organomet. Chem., 1989, 360, 409, L. Hegedus; Organotransition Metal Chemistry: Applications to Organic Synthesis, Stephen Davies, Vol. 2, 1982, p. 218; Organic Synthesis with Palladium Compounds, Jiro Tsuji, 1980.
The use of sulphonated arylphosphines has been reported for unrelated catalytic processes in aqueous media. Hydrocyanation of unsaturated organic compounds utilizing sulphonated triarylphosphines (STP) and Ni or Ni/Pd compounds has been reported (U.S. Pat. No. 4,087,452). Hydroformylation of propene using Rh and STP (U.S. 4,684,750), and telomerization of dienes using STP and Pd has been described (U.S. Pat. No. 4,142,060). The coupling of butadienes to phenols in the presence of Rh complexes and STP has been disclosed (U.S. Pat. No. 4,594,460). Asymmetric hydrogenation, hydroformylation and oligomerization reactions using sulphonated chiral arylphosphines and transition metal compounds has been reported (U.S. Pat. No. 4,654,176). The reduction of allyl chlorides to alkenes using STP, Pd salts and sodium formate has been described (Chem. Soc. Japan, 1986, 1463). Allyl chlorides have also been carbonylated to carboxylic acids using STP and Pd salts (Chem. Soc. Japan, 1988, 957).
The Pd catalyzed akylatin of aryl or vinyl halides with alkynes, alkenes, and aryl or vinylboronic acids has been extensively reported. Sonogoshira and others have described the alkynylation of aryl and vinyl halides with terminal acetylenes in the presence of Pd triphenylphosphine (TPP) complexes, base and CuI in non-aqueous media (Tet. Letters, 1975, 4467; Heterocycles, 1978, 9, 271). Robins and others have reported the coupling of iodonucleosides with terminal acetylenes under similar conditions in non-aqueous media (J. Org. Chem., 1983, 48, 1854). Aryl and vinyl halides may also be alkylated by alkenes in the presence of Pd TPP complexes and base in a non-aqueous medium in a reaction commonly known as the Heck reaction (J. Org. Chem., 1977, 42, 3903).
In a variation of the Heck reaction, aryl and vinyl mercurials can be coupled with alkenes utilizing PdCl.sub.4.sup.2- (J. Am. Chem. Soc., 1968, 90, 5518). Mertes has reported the coupling of 5-mercurialuridine monophosphates with alkenes in aqueous media using this method (J. Am. Chem. Soc., 1980, 102, 2033).
Suzuki and others have carried out the alkylation of aryl or vinyl halides with aryl or vinyl boronic acids (RB(OH).sub.2 where R=aryl, vinyl) utilizing Pd TPP complexes and a base in two phase systems where one phase comprises an aqueous phase (Synth. Comm., 1981, 11, 513; Chem. Lett., 1987, 25). In these systems, the Pd TPP complex and the aryl or vinyl halide are insoluble in the aqueous phase and soluble in the organic phase.
Alkylation at phosphorus has been observed by Hirao and Xu when aryl halides are treated with dialkylphosphites or dialkylphosphine oxides in the presence of base and Pd TPP complexes in non-aqueous media (Synthesis, 1981, 56; J. Chem. Soc., Chem. Commun., 1986, 1606).
The above catalysts are to be sure valuable but present significant problems; namely, these catalysts do not operate effectively in an aqueous medium on substrates which are soluble in an aqueous phase and relatively insoluble in an organic phase.